This invention relates generally to trains and other rail vehicles and more particularly to systems and methods for wireless communication with trains.
It is known to control braking, throttle, and other train functions remotely using distributed power control systems for locomotives (hereinafter Distributed Power or DP systems or simply DP), in which the operation of one or more remote locomotives (or group of locomotives forming a locomotive remote) is remotely controlled from the lead locomotive of the train, or an external site such as a control tower, by way of a radio or hard-wired communication system. One such radio-based DP system is commercially available under the trade name LOCOTROL, and is described in U.S. Pat. No. 4,582,280 (hereinafter “the '280 patent”).
Such systems often use radio repeaters to assist distributed power lead units in linking and commanding their remotes. For example, repeaters may be used in hilly territory, tunnels, or other areas where there is not a clear line-of-sight between the lead unit and remote.
These repeaters add additional radio traffic to the communication channel. In areas with heavy radio traffic, such as rail yards, the repeater activity can cause saturation in an already-heavily congested channel, and prohibit trains from linking or commanding remotes. The radio traffic congestion can be eliminated by disabling the repeater operation entirely; however this is an inefficient solution because it defeats the very purpose of having the repeaters in place.